I am new to this forum(to forums in general), I hope I am not posting this int he wrong place. I am thinking of running a 284 reamer down a nagant just to see what I can get out of it. Making it a 30-284r or a 7.62x54r improved. I don't know that much about ballistics and was hoping some one could help me out. It's mostly 30-284 data I am having trouble finding. I can find data for the 7.62x54r, but if some one has ballistics for both in similar loadings that would be a great help. Any info is helpfull including 7.62x54r data, but if you happen to have charts or graphs that would really really help me out.

I've got to say, that is about the strangest 'cat I've heard of in quite a while! A 30-284R, huh? The first thought that jumps to mind is the bolt face: How do you get it to fit the .473" head on the 284 case? The rim on the existing 7.62x54R is much larger, at .567", so there would be some work to do on the bolt. Or, am I missing something and you're planning to stick with the 7.62 brass?

I doubt you're going to find much published data, or even Internet data, for that wildcat. I've read a book or two on the subject of wildcats and definitely never heard of this one, so it's got to be pretty obscure. I am always interested in new ideas for wildcats, but the idea of building one on an existing Mosin-Nagant 91/30 action, with the original barrel, never would have occurred to me. They usually aren't the most accurate actions and the barrels are often worn and typically need .311" bullets to shoot well at all. Just a few thoughts that came to mind.

I figure the dimensions of the 7.62x54r are close enough that if one just reams for 284 win you ought to be able to fire form the 7.62x54r brass to size. I may only run the reamer down to 53.72mm (54mm) but I think I can make the brass stretch to the 55.12mm of the 284.
the 284 is only about 0.50 mm wider & 1mm longer than 54r. and the 54r has a lot of neck. there is a huge shoulder difference 18.5 degrees of the 54r to 30degrees of the 284. plus the original factory load pressures are very similar. I'm hoping some one can help me figure out what sort of gain I might be looking at.

You're looking at more than .020" expansion at the shoulder and (more importantly) .015" at the web. I'm not a gunsmith, but I really don't think that's gonna work out so good.

A lot of wildcats have been built on the 284 Winchester case, but aside from being of similar length, I think these two cartridges (284 and 7.62x54R) are just too different to pull off the 'cat you're thinking about.

Now, if you built a wildcat from 50 Alaskan brass, necked down to shoot .311" bullets, you could open up the bolt face slightly and set your shoulder out just past the existing chamber. You could be very simple about it and choose a .308" neck length and a 25 degree shoulder. You'd have a bottle-necked case with slightly more capacity and perhaps a little more operating pressure.

With your idea or mine, you won't gain much at all, especially if the plan is to stick with the original barrel and the limited options at .311". To be frank, I can't see the MN 91/30 as the action to throw money at, for your own wildcat. My opinion is worth exactly what you're paying me for it, but this 'cat is an even bigger money pit than most.

thanks for the incite. I had considered making the round from .375 flanged mag brass(on a press). but ruled it out some time ago. due brass cost. I'm sure 50 Alaskan brass is none to cheep either. I'm new to this, and not to worried about hacking up a mosin. My ultimate goal is more the experience gained, than the end result.

There is a video on YouTube showing how to do this.... Looks very straight forward, too easy to be true in fact. All the guy does in regards to the bolt face is hammer in the extractor until it will work with the smaller diameter. I don't even know if this is safe from a pressure standpoint but the guy makes it sound like it is a common conversion in Europe? The video is titled "Adapting a Mosin-Nagant 91-30 for Windchester wildcats" You'll have to search for it... Let me know what you think....

30-284 conversion is easy, and there is a lot of data if you know the magic words

that video looks awfully sketchy, especially the part where he modified the bolt face. I just have a thing for rimmed cartridges, I'm not sure why.

The 284 case would no problem in a mosin. The bolt face problem is solved the same way Bannerman did it in the early to mid 1900's. they just soldered in a bushing and cut the extractor groove slightly deeper. the 284 also fits the mossin magazine perfectly, perhaps better than the 54r. It fills the magazine such that anything bigger would require mag modification, and anything smaller including the 54r winds hp having a lot of slop in the mag. there would also wind up being a little work with minor parts like the interupter.

30-284's magic words
This is apparently a common conversion in France, you just have to Google "30-284 cartouche". Cartouche is french for cartridge, if you wand reloading data they use the word "rechargement". You will have to hit the translate option behind the search results (it works in Google, I cant attest to any other engine).

I am new to this forum(to forums in general), I hope I am not posting this int he wrong place. I am thinking of running a 284 reamer down a nagant just to see what I can get out of it. Making it a 30-284r or a 7.62x54r improved. I don't know that much about ballistics and was hoping some one could help me out. It's mostly 30-284 data I am having trouble finding. I can find data for the 7.62x54r, but if some one has ballistics for both in similar loadings that would be a great help. Any info is helpfull including 7.62x54r data, but if you happen to have charts or graphs that would really really help me out.

thanks for your help
Peder

Edited:

Forget that, Do it. I didn't realize it had been done and I didn't think it would fit the MN mag. But what do I know? Go for it.

Couldn't you use the .45-70 case and turn down the rim to fit the bolt? The .284 Win is .500" above the extractor groove while the .45-70 is .505" above the rim. The .284 is .070" longer, but you can get most of that back when the neck and shoulder are formed.

Another possible wildcat for the Mosin might be a .45-70 case resized with a shortened .308 Norma Magnum die. Neck OD of the .308 NM is .340" compared to .335" for the 7.62x54R. The case diameter at the shoulder of the .308 NM is .489" compared the .475" for the .284 Win.